Template refs for DOM access in Vue

Introduction

Template refs let you get a direct link to an HTML element or component in your Vue template. This helps you interact with the element in your code, like focusing an input or measuring size.

You want to focus an input box automatically when the page loads.

You need to read or change the value of a DOM element directly.

You want to measure the size or position of an element on the screen.

You want to call a method on a child component instance.

You want to control a video or audio element directly from your code.

Syntax

Vue

<template>
  <element ref="myRef"></element>
</template>

<script setup>
import { ref } from 'vue'

const myRef = ref(null)

// Access the element with myRef.value
</script>

The ref attribute in the template names the element or component.

In the script, you create a ref variable with null initial value.

Examples

This example focuses the input box when the component loads.

Vue

<template>
  <input ref="inputBox" />
</template>

<script setup>
import { ref, onMounted } from 'vue'

const inputBox = ref(null)

onMounted(() => {
  inputBox.value.focus()
})
</script>

This example logs the text inside the div after the component mounts.

Vue

<template>
  <div ref="box">Hello</div>
</template>

<script setup>
import { ref, onMounted } from 'vue'

const box = ref(null)

onMounted(() => {
  console.log(box.value.textContent)
})
</script>

This example shows how to call a method on a child component using a template ref.

Vue

<template>
  <ChildComponent ref="childComp" />
</template>

<script setup>
import { ref } from 'vue'
import ChildComponent from './ChildComponent.vue'

const childComp = ref(null)

function callChildMethod() {
  childComp.value.someMethod()
}
</script>

Sample Program

This component has an input box and a button. Clicking the button focuses the input box using a template ref. The input value is shown below and updates as you type.

Vue

<template>
  <input ref="nameInput" placeholder="Type your name" @input="updateValue" />
  <button @click="focusInput">Focus Input</button>
  <p>Input value: {{ inputValue }}</p>
</template>

<script setup>
import { ref } from 'vue'

const nameInput = ref(null)
const inputValue = ref('')

function focusInput() {
  nameInput.value.focus()
}

// Update inputValue when input changes
function updateValue() {
  inputValue.value = nameInput.value.value
}
</script>

<style scoped>
input {
  padding: 0.5rem;
  font-size: 1rem;
  margin-bottom: 0.5rem;
  display: block;
}
button {
  padding: 0.5rem 1rem;
  font-size: 1rem;
  cursor: pointer;
}
</style>

Important Notes

Template refs are only available after the component is mounted.

Access the DOM element with refVariable.value.

Use template refs carefully to avoid tightly coupling your code to the DOM structure.

Summary

Template refs let you directly access DOM elements or child components in Vue templates.

Use ref attribute in the template and a ref variable in the script.

They are useful for focusing inputs, reading element properties, or calling child component methods.

Practice

1. What is the main purpose of using template refs in Vue?

easy

A. To directly access DOM elements or child components from the template

B. To define reactive state variables

C. To create computed properties

D. To register global components

Solution

1. Step 1: Understand what template refs do

   Template refs provide a way to directly access DOM elements or child components inside Vue templates.

2. Step 2: Compare with other Vue features

   Reactive state variables and computed properties are for data management, not direct DOM access. Global components registration is unrelated.

3. Final Answer:

   To directly access DOM elements or child components from the template -> Option A

4. Quick Check:

   Template refs = direct DOM/component access [OK]

Hint: Template refs connect template elements to script variables [OK]

Common Mistakes:

• Confusing refs with reactive state
• Thinking refs create computed properties
• Assuming refs register components

2. Which of the following is the correct way to declare a template ref in Vue 3's <script setup> syntax?

easy

A. const myRef = ref(null);

B. let myRef = reactive(null);

C. const myRef = computed(() => null);

D. var myRef = ref('element');

Solution

1. Step 1: Recall how to declare refs in Vue 3 script setup

   Use const myRef = ref(null); to create a ref variable initialized to null.

2. Step 2: Check other options for correctness

   reactive is for objects, not refs. computed is for derived values. Using var is discouraged and 'element' is not a valid initial value for a ref to DOM.

3. Final Answer:

   const myRef = ref(null); -> Option A

4. Quick Check:

   Declare ref with ref(null) [OK]

Hint: Use ref(null) to declare template refs in script setup [OK]

Common Mistakes:

• Using reactive instead of ref for DOM refs
• Initializing ref with wrong value
• Using var instead of const

3. Given the following Vue 3 component code, what will be logged when the button is clicked?

<template>
  <input ref="inputRef" />
  <button @click="focusInput">Focus</button>
</template>

<script setup>
import { ref } from 'vue';
const inputRef = ref(null);
function focusInput() {
  console.log(inputRef.value.tagName);
  inputRef.value.focus();
}
</script>

medium

A. undefined will be logged and an error occurs

B. "inputRef" will be logged and the input will get focus

C. "INPUT" will be logged and the input will get focus

D. Nothing will be logged and no focus happens

Solution

1. Step 1: Understand what inputRef.value refers to

   inputRef is a ref to the input DOM element, so inputRef.value is the actual input element.

2. Step 2: Check what tagName returns and focus behavior

   inputRef.value.tagName returns the uppercase tag name "INPUT". Calling focus() sets keyboard focus on the input.

3. Final Answer:

   "INPUT" will be logged and the input will get focus -> Option C

4. Quick Check:

   inputRef.value.tagName = "INPUT" and focus works [OK]

Hint: Ref value holds the DOM element; tagName is uppercase [OK]

Common Mistakes:

• Logging the ref variable name instead of its value
• Forgetting to use .value to access the element
• Assuming tagName is lowercase

4. Identify the error in this Vue 3 code snippet using template refs:

<template>
  <div ref="box">Content</div>
</template>

<script setup>
import { ref } from 'vue';
const box = ref();
console.log(box.value.textContent);
</script>

medium

A. The ref variable 'box' is not initialized with null

B. Accessing box.value.textContent before DOM is mounted causes error

C. The ref attribute should be used as :ref instead of ref

D. Missing import of onMounted to access DOM safely

Solution

1. Step 1: Check ref initialization and usage timing

   box is declared as ref() without initial value, which defaults to undefined. Accessing box.value.textContent immediately runs before DOM is ready.

2. Step 2: Understand Vue lifecycle for DOM refs

   Template refs are assigned after the component mounts. Accessing them too early (during setup) causes box.value to be null or undefined, so textContent access fails.

3. Final Answer:

   Accessing box.value.textContent before DOM is mounted causes error -> Option B

4. Quick Check:

   Access DOM refs only after mount [OK]

Hint: Access refs after mount, not immediately in setup [OK]

Common Mistakes:

• Trying to read ref value before DOM exists
• Not initializing ref with null (less critical)
• Confusing ref attribute syntax

5. You want to create a Vue 3 component that automatically focuses an input element when the component is mounted using template refs. Which code snippet correctly implements this behavior?

hard

A. <template>
<input :ref="inputRef" />
</template>

<script setup>
import { ref, onMounted } from 'vue';
const inputRef = ref(null);
onMounted(() => {
inputRef.focus();
});
</script>

B. <template>
<input ref="inputRef" />
</template>

<script setup>
import { ref } from 'vue';
const inputRef = ref(null);
inputRef.value.focus();
</script>

C. <template>
<input ref="inputRef" />
</template>

<script setup>
import { ref, onMounted } from 'vue';
const inputRef = ref(null);
onMounted(() => {
inputRef.value.focus();
});
inputRef.value.focus();
</script>

D. <template>
<input ref="inputRef" />
</template>

<script setup>
import { ref, onMounted } from 'vue';
const inputRef = ref(null);
onMounted(() => {
inputRef.value.focus();
});
</script>

Solution

1. Step 1: Use onMounted to run code after DOM is ready

   To safely access the input element, focus must be called inside onMounted lifecycle hook.

2. Step 2: Access the DOM element via inputRef.value and call focus()

   inputRef is a ref initialized to null, and inputRef.value holds the DOM element after mount. Calling inputRef.value.focus() sets focus correctly.

3. Final Answer:

   Code snippet C correctly uses onMounted and inputRef.value.focus() -> Option D

4. Quick Check:

   Use onMounted + inputRef.value.focus() [OK]

Hint: Focus input inside onMounted using inputRef.value.focus() [OK]

Common Mistakes:

• Calling focus outside onMounted before DOM ready
• Using :ref instead of ref attribute
• Calling focus on ref instead of ref.value